To study the intact and altered cerebral vasculature in order to understand the vascular events that occur in cerebral edema. To define the distribution and the role of the pericyte in blood vessels of the central nervous system. To study the repair of cerebral blood vessels after injury in order to define the morphological events that lead to reconstitution of the integrity of the cerebral vasculature and restitution of the blood-brain barrier. To continue to study the fate of protein in cerebral edema and to explore the possibility that exogenous protein may be used to localize sites of antibody formation in the central nervous system. To study the effects of therapeutic agents on the intact and altered cerebral vasculature.